An electric vehicle such as an electric automobile and a hybrid vehicle uses at least an electric motor as a part of a power source for travelling. Therefore, as described in Patent Literature 1, the electric vehicle necessitates using a large-capacity battery as a power source of the electric motor.
However, it is necessary to take a long time for charge of such a large-capacity battery which should be carried out when a rate of charge (SOC) of the battery is lowered. For this reason, it will be more convenient if the battery is replaceable with a charged battery such that the electric vehicle can quickly restart the travelling.
Even though an electric vehicle is not such a battery replacement type electric vehicle, the battery must be replaced with a new one when the battery is deteriorated due to long-time use with repeated charge. Accordingly, the electric vehicle is constructed such that replacement with the battery can be carried out as described in Patent Literature 1.